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Modification of the RLA model for presenting a cluster system of a composite material with a fractal filler structure
Get PDFThe paper proposes a modification of the diffusion-limited aggregation model to study the properties of a cluster system. A computational experiment to determine the mutual influence of the sticking probability and the volume concentration of particles on the formation of fractal clusters in a cluster system was carried out in accordance with the second-order orthogonal central compositional plan (OCCP). As a result of a computational experiment in accordance with the OCCP, an equation was obtained for the dependence of the mass fractal dimension of clusters on the volume of particle concentration and the probability of adhesion of diffusing particles and cluster particles in the adhesion zone. This dependence was obtained in a range of volume concentration of particles from 2 to 5 % and the probability of adhesion of diffusing particles and particles of clusters in the adhesion zone from 0.2 to 1.The paper proposes a modification of the diffusion-limited aggregation model to study the properties of a cluster system. A computational experiment to determine the mutual influence of the sticking probability and the volume concentration of particles on the formation of fractal clusters in a cluster system was carried out in accordance with the second-order orthogonal central compositional plan (OCCP). As a result of a computational experiment in accordance with the OCCP, an equation was obtained for the dependence of the mass fractal dimension of clusters on the volume of particle concentration and the probability of adhesion of diffusing particles and cluster particles in the adhesion zone. This dependence was obtained in a range of volume concentration of particles from 2 to 5 % and the probability of adhesion of diffusing particles and particles of clusters in the adhesion zone from 0.2 to 1
The proton flux influence on electrical characteristics of a dual-channel hemt based on GaAs.
Get PDFThe results of the simulation the influence of the proton flux on the electrical characteristics of the device structure of dual-channel high electron mobility field effect transistor based on GaAs are presented. The dependences of the drain current ID and cut-off voltage on the fluence value and proton energy, as well as on the ambient temperature are shown.The results of the simulation the influence of the proton flux on the electrical characteristics of the device structure of dual-channel high electron mobility field effect transistor based on GaAs are presented. The dependences of the drain current ID and cut-off voltage on the fluence value and proton energy, as well as on the ambient temperature are shown
Geometrization of the theory of electromagnetic and spinor fields on the background of the Schwarzschild spacetime
Get PDFThe geometrical Kosambi–Cartan–Chern approach has been applied to study the systems of differential equations which arise in quantum-mechanical problems of a particle on the background of non-Euclidean geometry. We calculate the geometrical invariants for the radial system of differential equations arising for electromagnetic and spinor fields on the background of the Schwarzschild spacetime. Because the second invariant is associated with the Jacobi field for geodesics deviation, we analyze its behavior in the vicinity of physically meaningful singular points r = M, ∞. We demonstrate that near the Schwarzschild horizon r = M the Jacobi instability exists and geodesics diverge for both considered problems.The geometrical Kosambi–Cartan–Chern approach has been applied to study the systems of differential equations which arise in quantum-mechanical problems of a particle on the background of non-Euclidean geometry. We calculate the geometrical invariants for the radial system of differential equations arising for electromagnetic and spinor fields on the background of the Schwarzschild spacetime. Because the second invariant is associated with the Jacobi field for geodesics deviation, we analyze its behavior in the vicinity of physically meaningful singular points r = M, ∞. We demonstrate that near the Schwarzschild horizon r = M the Jacobi instability exists and geodesics diverge for both considered problems
Оценка приоритетов управлений на основе матрицы парных сравнений
Get PDFThe article contains a description of the model and approach for determining the weights of controls (other objects) based on a matrix of pairwise comparisons. The initial data in the matrix of paired comparisons implicitly specify interval estimates for comparison of controls. Interval estimates can be constructed relatively easily using Harrington's fuzzy metric scale. A heuristic method for determining the priorities of controls is proposed, which seeks to obtain weights (priorities) of controls that deviate minimally from the boundary values of the weight intervals.The latter are easy to find using the system of relations, on the basis of which the matrix of pairwise comparisons of controls is built. To assess the statistical adequacy of the found control priorities, the determination coefficient is used, the value of which at the level of 80 % and above is considered practically acceptable for applications. The critical value of the coefficient of determination can be determined, for example, using the Fisher criterion. If the conditions of statistical adequacy are not met, the initial data in the matrix of paired comparisons should be revised. An example is provided to illustrate the method described in the article. The main advantages of the approach described in the article are the flexibility of the choice of interval estimates for pairwise comparison of controls, the relative simplicity of computational calculations, and the ability to control the calculation results using statistical criteria. The described method develops the authors' approach to the adoption of anti-crisis management by adapting management priorities to the conditions of the production system and its environment.В статье содержится описание модели и подхода для определения весов управлений (иных объектов) на основе матрицы парных сравнений. Исходные данные в матрице парных сравнений в неявном виде задают интервальные оценки для сравнения управлений. Интервальные оценки можно сравнительно просто построить, используя нечеткую метрическую шкалу Харрингтона. Предлагается эвристический метод определения приоритетов управлений, который стремится получить веса (приоритеты) управлений, минимально отклоняющиеся от граничных значений интервалов весов. Последние легко отыскать с помощью системы отношений, на базе которых построена матрица парных сравнений управлений. Для оценки статистической адекватности найденных приоритетов управлений используется коэффициент детерминации, значение которого на уровне 80 % и выше считается практически приемлемым для приложений. Критическое значение коэффициента детерминации может быть определено, например, с помощью критерия Фишера. При невыполнении условий статистической адекватности следует пересмотреть исходные данные в матрице парных сравнений. Приведен пример, иллюстрирующий описанный в статье метод. Основными достоинствами изложенного в статье подхода являются гибкость выбора интервальных оценок при парном сравнении управлений, относительная простота вычислительных расчетов, возможность контроля результатов расчетов с помощью статистических критериев. Описанный метод развивает подход авторов к принятию антикризисных управлений за счет адаптации приоритетов управлений к условиям производственной системы и ее окружения
Разборчивость и узнаваемость речи диктора при электроакустических преобразованиях в трансформаторе
Get PDFThe purpose of the article is to outline the procedure and the results of the study of the influence of the distance from the sound source to the transformer on speech intelligibility and speaker recognition by voice during electro-acoustic conversion in a transformer. Of all the existing methods for measuring speech intelligibility and voice recognition, the objectified method of articulatory syllabary tables was used. The choice of the method is due to the fact that with a large number of dictated and, accordingly, adopted syllables, the influence of various factors is averaged out. Averaging also occurs if different groups of speakers and auditors take part in the tests. This is the objectivity of the articulatory method. Objective results can also be obtained by using speech to precisely reproduce sound combinations that do not have a semantic load, since when receiving words or phrases, it is possible to think out and restore the elements of the speech distorted by the communication path. The experimental procedure was determined. For the study, a transformer was used as an electroacoustic transducer, and a multifunctional search device ST031M “Piranha” was used as a control and measuring equipment. The selection of speakers and auditors was carried out for the research team. The selection was carried out among men and women between the ages of 18 and 30 who had no obvious speech and hearing impairments and were native speakers of the Russian language. The dependences of the values of the level of speech intelligibility and recognition of the speaker's voice on the distance between the sound source and the transformer are derived. The distances from the sound source to the transformer are determined, at which speech intelligibility corresponds to different quality classes according to GOST 16600-72.Целью статьи является изложение порядка проведения и результатов исследования влияния расстояния от источника звука до трансформатора на разборчивость речи и узнаваемость диктора по голосу при электроакустическом преобразовании в трансформаторе. Из всех существующих методов измерения разборчивости речи и узнаваемости голоса диктора использовался объективизированный метод артикуляционных слоговых таблиц. Выбор метода обусловлен тем, что при большом числе продиктованных и соответственно принятых слогов влияние различных факторов усредняется. Усреднение происходит также, если в испытаниях принимают участие различные группы дикторов и аудиторов. В этом и заключается объективизированность артикуляционного метода. Получить объективные результаты также помогает воспроизведение с помощью речи именно звукосочетаний, не имеющих смысловой нагрузки, так как при приеме слов или фраз можно додумать и восстановить искаженные трактом связи элементы речи. Была определена методика проведения эксперимента. Для исследования в качестве электроакустического преобразователя использовался трансформатор, а в качестве контрольно-измерительной аппаратуры – многофункциональный поисковый прибор ST031M «Пиранья». В состав бригады для проведения исследования был выполнен отбор дикторов и аудиторов. Отбор проводился среди мужчин и женщин в возрасте от 18 до 30 лет, не имеющих явных дефектов речи и слуха и являющихся носителями русского языка. Выведены зависимости значений уровня разборчивости речи и узнаваемости голоса диктора от расстояния между источником звука и трансформатором. Определены расстояния от источника звука до трансформатора, при которых разборчивость речи соответствует различным классам качества согласно ГОСТ 16600-72
Influence of radiation exposure on the properties of dielectric layers based on anodic aluminum oxide
Get PDFDevices that are used in the aerospace industry must operate in extreme conditions, so it is important to understand how the properties of materials change under the influence of radiation and low temperatures. Anodic aluminum oxide, due to its mechanical and dielectric properties, is widely used in electronic devices with a high degree of integration. Radiation exposure can lead to degradation of the electrophysical parameters of dielectric films and can also change their chemical composition. The methods for studying the effect of radiation exposure on the dielectric properties of films are shown in this article. The research has been carried out and the results of the influence of α-particles on the dielectric properties of a porous film of anodic aluminum oxide during the influence of low temperature are presented.Devices that are used in the aerospace industry must operate in extreme conditions, so it is important to understand how the properties of materials change under the influence of radiation and low temperatures. Anodic aluminum oxide, due to its mechanical and dielectric properties, is widely used in electronic devices with a high degree of integration. Radiation exposure can lead to degradation of the electrophysical parameters of dielectric films and can also change their chemical composition. The methods for studying the effect of radiation exposure on the dielectric properties of films are shown in this article. The research has been carried out and the results of the influence of α-particles on the dielectric properties of a porous film of anodic aluminum oxide during the influence of low temperature are presented
Atom species energy dependence on magnetic configurations in the perovskite yttrium orthoferrite
Get PDFThe article represents the results of studying of the influence of atom species in the perovskite multiferroic yttrium orthoferrite YFeO3 on magnetic configurations by ab-initio methods. Four magnetic configurations possible in magnetic sublattice that were formed by iron atoms were analyzed. It is shown that different magnetic orderings change the lattice parameters and the ions occupied positions while preserving symmetry of the unit cell, the lowest state responds G-AFM type magnetic ordering. The lattice parameters are in good relevant published experimental data. The atom species energy dependence shows that the main role in magnetic properties goes to iron and oxygen. In the ground state, magnetic properties relate with Dzyaloshinskii – Moriya interaction, while in other configurations, these relate with superexchange through Fe- O-Fe chains. Obtained results are useful for analyzing and designing straintronics devices. Also, the results can be interesting for interpretation and predicting magnetic properties of partially or fully substituted orthoferrites including substitution on rare-earth elements.The article represents the results of studying of the influence of atom species in the perovskite multiferroic yttrium orthoferrite YFeO3 on magnetic configurations by ab-initio methods. Four magnetic configurations possible in magnetic sublattice that were formed by iron atoms were analyzed. It is shown that different magnetic orderings change the lattice parameters and the ions occupied positions while preserving symmetry of the unit cell, the lowest state responds G-AFM type magnetic ordering. The lattice parameters are in good relevant published experimental data. The atom species energy dependence shows that the main role in magnetic properties goes to iron and oxygen. In the ground state, magnetic properties relate with Dzyaloshinskii – Moriya interaction, while in other configurations, these relate with superexchange through Fe- O-Fe chains. Obtained results are useful for analyzing and designing straintronics devices. Also, the results can be interesting for interpretation and predicting magnetic properties of partially or fully substituted orthoferrites including substitution on rare-earth elements
Формирование и свойства композитных гетеросистем на основе макропористого кремния, графитоподобного нитрида углерода и полупроводниковых соединений
Get PDFThe possibility of pyrolytic synthesis of composite heterosystems based on macroporous silicon, graphitic carbon nitride and wide band semiconductors zinc oxide and zinc sulfide (g-C3N4/ZnO/ZnS) from a mechanical mixture of thiourea and zinc acetate at 500 – 600 °C was shown. The obtained material study by scanning electron microscopy and energy dispersive X-ray spectroscopy showed a uniform filling of macroporous silicon with the composite g-C3N4/ZnO/ZnS with the formation of a continuous composite film on the surface. The photoluminescence of the samples was controlled by the synthesis temperature. Increase of photoluminescence leads to shift of luminescence maximum in high energy range from 544 to 516 nm. It was found that photocatalytic activity of composite heterosystems obtained at a lower temperature is higher due to more developed surface morphology and smaller bandgap width. The materials obtained can be used to create photocatalytic coatings and functional layers of optoelectronic devices.Показана возможность пиролитического синтеза композитных гетеросистем на основе макропористого кремния, графитоподобного нитрида углерода и широкозонных полупроводников оксида и сульфида цинка (g-C3N4/ZnO/ZnS) из механической смеси тиомочевины и ацетата цинка при температуре 500 – 600 °C. Исследование полученных материалов методами сканирующей электронной микроскопии и энергодисперсионной рентгеновской спектроскопии показало равномерное заполнение макропористого кремния композитом g-C3N4/ZnO/ZnS с образованием сплошной композитной пленки на поверхности. Фотолюминесценция образцов контролируется температурой синтеза. Ее увеличение приводит к сдвигу максимума свечения в диапазон больших энергий с 544 на 516 нм. Установлено, что фотокаталитическая активность композитных гетеросистем, полученных при меньшей температуре, выше, что обусловлено более развитой морфологией поверхности и меньшей шириной запрещенной зоны. Полученные материалы могут быть использованы для создания фотокаталитических покрытий и функциональных слоев оптоэлектронных приборов
Simulation of High-Power Klystrons with Heterogeneous Focusing Magnetic Field
Get PDFThe work shows a significant effect of the focusing magnetic field on the output characteristics of the klystron. When the calculations are done using nonlinear one-dimensional models, optimization of the parameters makes it possible to obtain versions of devices with the efficiency of 0.8 – 0.9 and higher. However, when testing these options using nonlinear two-dimensional models that take into account the radial motion of electrons, there is a significant discrepancy in the output characteristics obtained from the one-dimensional and two-dimensional models. This is due to the fact that during the motion of the electron beam, the radii of the leading centers of the large particles change the coefficients of interaction of the particle fields with the electromagnetic fields of the resonators change, which leads to a change in the output characteristics of the klystrons: efficiency, output power, and gain. On the other hand, it seemed that setting a large focusing magnetic field to exclude the radial motion of particles could eliminate this drawback, however, another problem arises here - the magnetic system for focusing becomes unacceptably large and it is technically difficult to obtain magnetic induction values of more than 2 T (the weight of the magnetic system can be several hundred kilograms). Therefore, one should choose the magnetic field induction for focusing the electron beam no more than 1T. In this paper, a twodimensional nonlinear mathematical model (2.5D) is proposed that takes into account the azimuthal component in the equations of motion. In the model, the induction of the focusing magnetic field is set in the form of tables. This makes it possible to set the inhomogeneity of the magnetic field at any place in the interaction space of the klystron. The calculation of a powerful relativistic klystron with an accelerating voltage of 1000 kV and the beam current of 250 A was carried out. The use of an inhomogeneous magnetic field makes it possible to reduce the deposition of electrons in the region of the gaps. Therefore, a decrease in the electron deposition leads to an increase in the durability of klystrons.
Многопоточная реализация свертки на основе блочных методов
Get PDFA multithreaded convolution implementation based on block algorithms is considered. Convolution is essentially the basis of many methods that solve the problem of determining the degree of similarity or independence of two processes, in other words, when it is necessary to determine the degree of correlation. The algorithm itself is executed with a significant delay, because for its execution it is necessary to accumulate the entire signal and then process it. The analysis showed that one of the possible ways to reduce time costs is a multithreaded implementation of convolution based on block algorithms. The article shows the main features of the convolution implementation by the overlap method with addition and the overlap method with addition, as well as numerical examples. The results obtained show that the application of these methods without the use of a window function leads to significant distortions in the signal spectrum. Based on the results of the analysis, a universal scheme for performing convolution based on multithreaded processing of an input data block is proposed. This allows to achieve a good compromise between computational complexity, system architecture, and time costs.Рассмотрена многопоточная реализация свертки на основе блочных методов. Свертка по своей сути является основой множества методов, которые решают задачу определения степени похожести или независимости двух процессов, иными словами, когда необходимо определить степень корреляции. Алгоритм свертки выполняется с существенной задержкой, так как для его выполнения необходимо накопить весь сигнал и после этого осуществить обработку. Анализ показал, что одним из возможных способов снижения временных затрат является многопоточная реализация свертки на основе блочных методов. Раскрыты основные особенности реализации выполнения свертки методом перекрытия со сложением и методом перекрытия с добавлением, а также приведены численные примеры. Полученные результаты показывают, что применение данных методов без использования оконной функции приводит к возникновению существенных искажений в спектре сигнала. Предложена универсальная схема выполнения свертки на основе многопоточной обработки блока входных данных. Это позволяет достичь хорошего компромисса между вычислительной сложностью, архитектурой системы и временными затратами